Efforts will be continued to separate the native mycobacterial antigens present in culture filtrate of M. tuberculosis H37Rv. Biochemical simplification will be followed by medium-scale preparative polyacrylamide gel electrophoresis, the ultimate goals being to study individual antigens in Type IV mycobacterial hypersensitivity and to prepare monospecific precipitating rabbit antisera to individual antigens. Comparative studies of anti-dinitrophenyl antibodies will be undertaken after synthesis of anti-DNP in inbred guinea pigs, both in normal animals and animals rendered specifically unresponsive to acquisition of contact-type (Type IV) sensitivity to dinitrochlorobenzene.